Cotter pin



Aug. 31, 1965 c. c. FARoNl 3,203,301

COTTER PIN Filed Nov. 9, 1962 INVENTOR.

CHARLES C. FARON/ United States Patent O 3,203,301 COTTER PIN Charles C. Faroni, Summit, NJ., assignor to Elastic Stop Nut Corporation of America, Union, NJ., a corporation of New Jersey Filed Nov. 9, 1962, Ser. No. 236,622 1 Claim. (Cl. 85-8.1)

This invention relates to fastening devices and more particularly to cotter pins and similar devices having means for increasing the fatigue life of the devices.

It is an object of this invention to provide an improved fastening device which has a greatly increased fatigue life.

It is another object of this invention to provide an improved fastening device which has means for damping vibratory motion between the device and other members with which it is assembled.

It is still another object of this invention to provide an improved cotter pin which includes means for reducing metal-to-metal contact between the cotter pin and other members with which it is assembled.

It is yet another Aobject of this invention to provide an improved cotter pin which includes means for reducing rotational movement between nuts and bolts with which it is assembled.

It is still another object of this invention to provide improved cotter pins which may be reduced in size and weight and yet have increased fatigue life in relation to standard size cotter pins.

This invention may be briefly described as an article of manufacture comprising a cotter pin or similar fastening device and means surrounding a portion of the cotter pin or device for damping motion between the cotter pin or device and other members with which it is assembled.

Additional objects and advantages of an article of manufacture embodying the present invention will be more fully understood from the following description when read in connection with the accompanying drawings in which:

FIG. 1 is a view in vertical section of an article of manufacture embodying the present invention;

FIG. 2 is a view in vertical section of an article of manufacture as shown in FIG. 1 assembled with a bolt and a nut;

FIG. 3 is a top view of the assembly illustrated in FIG. 2 with the bolt being shown in cross section;

FIG. 4 is a view in vertical section of a modified article of manufacture according to the present invention;

FIG. 5 is a View in vertical section of another article of manufacture embodying the present invention;

FIG. 6 is a view in vertical section of an article of manufacture as shown in FIG. 5 assembled with a bolt and a nut;

FIG. 7 is a top view of the assembly illustrated in FIG. 6 with the bolt being shown in cross section; and

FIG. 8 is a view taken along the line 8-8 of FIG. 5.

Referring now to the drawings there is shown a fastening device 10, which for purposes of illustration, is in the form of a cotter pin which consists of a piece of halfround metal wire that has been return bent to define a head portion 12 having an eyelet and a shank portion 14 having a pair of legs 16 and 18. The fiat faces of the legs 16 and 18 are presented to each other and leg 18 is preferably somewhat shorter than leg 16. The half-round wire will usually be one of the steels heretofore found suitable for cotter pin service.

As heretofore stated it is one of the objects of this invention to increase the fatigue life of the cotter pin and to obtain this result a portion of the cotter pin is surrounded with means for damping the motion between the 3,203,301 Patented Aug. 31, 1965 pin and members with which it is assembled. It will be apparent that there are a number of different materials which will damp the Vibratory motion and even though the material is illustrated as a plastic in the drawings a.

number of different materials such as an elastomer are available which will perform the same function.

Referring now to FIG. l, there is illustrated a cotter pin 10 having a section of its shank portion 14 surrounded by a circular piece of damping material 20 such as nylon or Teflon. In order to retain the damping material 20 on the shank, each leg 16, 18 is formed with a joggle 22 so that the damping material can be molded through the joggle. An alternative method of retaining the damping material on the shank 14 is shown in FIG. 4. In this case, the material is formed in the shape of a tube 24 with an axial opening 26 the diameter of which is normally slightly less than that of the shank portion 14. Therefore, the tube is stretched over the legs 16 and 18 so that the contraction of the material retains the tube in its proper position on the shank 14.

For purposes of describing the results obtained by the new article of manufacture, I have depicted in FIG. 2 the cotter pin 10 mounted in a slot 27 in a castellated nut 28 and through a hole 30 in a bolt 32.

In the preferred method of cotter pin installation, the head portion 12 should be firmly seated in the slot of the nut with the axis of the eyelet at right angles to the bolt shank and the head positioned firmly against the bolt to prevent looseness. The legs should be bent as illustrated in FIG. 2.

In the preferred embodiment of the fastening device 10 illustrated in FIG. l, the length of the body of damping material should be slightly longer than the hole 30 in the bolt 32 so that when the pin is seated in the slot 26 the damping material 20 will are out at one end and prevent metal-to-metal Contact between the legs 16 and 18 and the edge of the hole 30. It will be apparent that the damping material will prevent wear of both the cotter pin 10 and the wall of the hole 30. Since the damping material completely surrounds the shank of the pin which extends through the hole 30, the vibration of the pin in the hole is greatly reduced thereby increasing the fatigue life of the cotter pin 10.

For best results, the diameter of the body of damping material should be substantially the same as the diameter of the hole 30 through the bolt 32. However this relationship is not essential and any diameter of the circular piece 20 will give the desired result of increased fatigue life of the cotter pin 10.' Furthermore, I have found that even if the shank portion 14 of the cotter pin 10 is reduced in size, i.e. a smaller size half-round wire, by using a body of damping material the fatigue life of the pin will be increased and the weight will be reduced.

A modified form of cotter pin 10, which is illustrated in FIGS. 5 through 8, includes elements similar to those illustrated in FIG. 1 and like parts will be designated by like reference numerals. As best seen in FIG. 5, the damping material 20 in this embodiment of the invention is in the form of a continuous body surrounding the head portion 12 and sections of the shank portion 14. To retain the body of damping material 20 on the pin 10, the material is molded through the eyelet 34, but it will be apparent that the same means as disclosed in FIG. 1 could be used.

Illustrated in FIGS. 6 and 7 is the manner in which the modified form of pin 10 would be mounted in the slot 27 in the castellated nut 28 and through the hole 30 n the bolt 32. Since the head portion 38 of the pin is surrounded by damping material 20 it will be evident that no metal-to-metal contact will be experienced between the head 12 of the pin 10 and the sides 29 of the slot in the nut 28.

As best seen in FIG. 8 the sides of the body of material 20 surrounding the head portion 12 of the pin are tapered at 36, so that the body of damping material 20 adjacent the head 12 can be wedged into the slot 26 as shown in FIG. 7 thereby reducing rotation of the nut on the bolt as Well as reducing vibration of the head 12 in the slot 26. In certain instances it may be desirable to surround only the head portion of the cotter pin with damping material.

It is to be understood that the above detailed description of an embodiment of the invention is provided by Way of example and is not intended to restrict the invention. Various details of design and construction may be modied without departing from the true spirit and scope of the invention as defined in the claim.

What I claim is:

An article of manufacture comprising a metallic split cotter pin having a looped head portion and a shank portion in the form of a pair of overlying segments integral ends remote from said head portion, a portion of each of said segments being deflected apart to provide an opening therebetween at a location between said head portion and said free ends, and a body of nonmetallic resilient material for damping motion between said pin and other members with which it is assembled, said body surrounding said shank portion and extending through said opening, said head portion and said free ends being free of said material.

References Cited by the Examiner UNITED STATES PATENTS 2,464,381 3/49 Donaldson et al. 87-7 2,510,897 6/50 MacLean et al. 85-8.1 2,678,585 5/54 Ellis.

FOREIGN PATENTS 393,420 6/ 33 Great Britain.

with and extending from said head portion and having free 20 EDWARD C- ALLEN Primary Examifle- 

